Cover for produce carton

ABSTRACT

A berry container and its contents are enclosed by a one-piece cover differential-pressure formed of very thin thermoplastic material suitable for packaging, protecting and displaying the berries. The cover is cup-shaped and the interior of each side is formed with a narrow shoulder which seats on the upper lip of the container to index the cover relative the container. A pair of differential-pressure formed, rounded protuberances positioned at each corner beneath the shoulder are cammed over the container lip to releasably lock the cover lip to the container. Increased resistance to deflection by both vertical and transverse loads is obtained by forming into the sides a series of longitudinally spaced vertically standing ribs.

United States Patent [1 1 Medendorp Sept. 24, 1974 1 COVER FOR PRODUCE CARTON [75] Inventor: Roger L. Medendorp, Grand Rapids,

Mich.

[73] Assignee: Kirkhof Manufacturing Corporation, Grand Rapids, Mich.

[22] Filed: Aug. 31, 1972 [21] Appl. No.: 285,344

[52] U.S. Cl 220/60 R, 206/4534, 229/43 51 1nt.Cl ..B65d 43/10 [58] Field of Search 220/60 R; 206/4534; 229/25, 43

[56] References Cited UNITED STATES PATENTS 3,001,665 9/1961 Tomarin 220/60 R Primary Examiner-George E. Lowrance Attorney, Agent, or Firm-Price, Heneveld, Huizenga & Cooper [5 7 ABSTRACT A berry container and its contents are enclosed by a one-piece cover differential-pressure formed of very thin thermoplastic material suitable for packaging, protecting and displaying the berries. The cover is cup-shaped and the interior of each side is formed with a narrow shoulder which seats on the upper lip of the container to index the cover relative the container. A pair of differential-pressure formed, rounded protuberances positioned at each corner beneath the shoulder are cammed over the container lip to releasably lock the cover lip to the container. Increased resistance t0 deflection by both vertical and transverse loads is obtained by forming into the sides a series of longitudinally spaced vertically standing ribs.

16 Claims, 4 Drawing Figures COVER FOR PRODUCE CARTON BACKGROUND OF THE INVENTION This invention relates to the packaging of merchandise, and particularly fruit such as berries which decompose rapidly if damaged.

In the merchandising of fruit such as berries, it is desirable to make a display in a manner so that the berries are clearly visible to the customer and yet held in an orderly relationship and protected against breakage by normal handling and shipping. The berries are usually held in an open topped container comprised of plastic or paper pulp which has sufficient flexibility to absorb shock and yet is sufficiently rigid to prevent crushing by either vertical or transverse loads. Generally the container includes openings for breathing. The berries are generally piled in pyramidal fashion above the top of the container and enclosed by some type of cover. Until recently, the containers have been covered by a thin sheet of plastic wrapper such as Saran wrap. This has been replaced in large part by a more rigid cover to increase the protection and allow vertical stacking of the containers one on the other. In addition to overall protection and shipping convenience however, cost is also a significant factor.

Many covers utilized in displaying and shipping berries have been proposed but it has been exceptionally difficult to provide covers of a very thin plastic material which has sufficient shock absorption to prevent damage to the berries by handling and shipping and yet have sufficient vertical and handling and shipping and yet have sufficient vertical and transverse strength to provide the required degree of load support when packages are superimposed or arranged side by side in shipping containers. In addition, it is desirable to provide some type of latch means which allows the cover to be releasably locked to the container to prevent unintentional removal of the cover while at the same time permitting easy entry for withdrawal of part or all of the contents. In addition to the latching function, it is also desirable to have a latch means which indexes the cover relative to the container when the cover is applied to the container. The prior art has made attempts to provide a cover with one or more of these desired features but has failed to produce one that is both easy to manipulate without easily damaging the berries contained therein and is relatively inexpensive.

SUMMARY OF THE INVENTION The packaging and distribution of fruits such as srrawberries and the like is generally distributed in pints or quarts and displayed in a container having an open top covered by a cover means which shields and protects the strawberries confined therein.

In accordance with the invention, the cover is formed of a resilient one-piece material having a top and downwardly extending sides. The sides include one or more rounded protuberances extending inwardly at the corners. One or more of the protuberances are cammed over the upper margin of the container sides to index and latch the cover to the container.

In accordance with a narrower aspect of the invention, the cover is differential-pressure formed in one piece from a sheet of transparent material into a general cup-shape. Each of the sides include anupper and lower portion separated by an internal shoulder extending generally normal to the sides, said shoulder seating on the lip of the container to index said cover relative thereto. In addition, each side includes a rounded protuberance positioned beneath the shoulder which is cammed over the lip portion of the container to releasably latch the cover to the container.

In a more narrower aspect of the invention, the upper portions of the sides include one or more vertical standing ribs spaced laterally from each other while the top includes a central recess forming an upstanding wall around the recess. The rib and wall portions increase the overall strength of the cover from both vertical and transverse loading while the shoulder distributes and bears the weight of superimposed containers stacked vertically.

The cover of the invention is preferably vacuumformed and provides an extremely inexpensive thin walled plastic cover which seats positively on the container with the camming of the latch means being smooth for both insertion and removal. Furthermore, the ribbing and recessing provisions provide an extremely strong cover for vertical stacking, etc.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a produce container and cover in accordance with the invention;

FIG. 2 is a plan view of the cover;

FIG. 3 is a fragmentary elevation view in crosssection of the cover and continer; and

FIG. 4 is an enlarged fragmentary sectional view of the latch means which locks the cover to the container.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, FIG. 1 illustrates a container 10 which is particularly adapted for packaging, protecting and displaying frangible fruit items such as strawberries and the like. Container 10 includes an open top 12 with the berries confined therein generally being stacked above open top 12 and in general pyramidal fashion. A cover 14 is provided which when positioned over container 10 fully encloses the open top of the container and protects and shields the berries contained therein from inadvertent damage. The combined volume of the container and cover generally holds a defined volume of berries such as a pint or quart.

Container 10 has a general box-shape with a generally planar bottom 16 on which the container rests and four interconnected sides 18 which extend upwards from bottom 16. The upper margin 20 (FIG. 4) of sides 18 includes a lip portion 22 which projects out slightly away from sides 18 defining a generally horizontal surface 24 which as will be described more clearly hereinafter acts as a keeper for the latch mechanism of cover 14.

A plurality of vertically oriented openings 26 are shown to extend vertically in sides 18 and extend also inwardly a portion into bottom 16. Openings 26 without detracting from the protection of the berries confined therein permit ventilation which is important in retarding premature decomposition. The container 10 shown in the drawings is comprised of a molded paper pulp formed as an integral piece. The composition and exact shape of container 10 however, may vary without affecting its unique combination with the cover 14 of the invention. For example, many containers in use today are formed of some type of molded plastic.

Referring now to FIGS. 3 and 4, cover 14 is comprised of a very thin thermoplastic material which is preferably differential-pressure formed. The pressure differential may be a positive or negative (vacuum) differential. In some cases, both types may be utilized. One method utilized is to place a sheet of plastic on a heating plate. A die having a configuration corresponding to that desired for the ultimate product is then placed over the upper surface of the sheet by means of a press. The sealing and heating surface has means to allow the passage of air to the underside of the plastic sheet whereby a pressure differential can be established between the opposite sides of the plastic sheet.

The cover includes a generally planar top 30 and downwardly extending sides 32 with an open bottom 34 for receipt of the upper margin 20 of container 10. Each side 32 includes an upper portion 36 and lower portion 38 interconnected by a flat horizontally extending shoulder 40 which seats on the upper margin 20 of container when cover 14 is properly positioned on container 10. The width of shoulder 40 is selected so that its inner margin 42 is closely aligned with the inner margin 44 of lip 22 when the cover is seated on the container. This prevents the accidental pinching of berries contained in container 10 as the cover is seated on the container. Any pinching or brusing of the berries, of course, expedites and proliferates a premature decomposition of the berries in the container. Preferably, the outer margin 46 of shoulder 40 is aligned with the outer margin 48 of lip 22 so that the lower portion 36 of the sides 32 extends downwardly and snugly over lip portion 22. Thus, the width of shoulder 40 corresponds closely to the width of upper margin of the container. Preferably, the lower portion 38 of sides 32 are very slightly inclined outwardly to facilitate placing the cover on the container. Hence, the overall size of the lower margin 50 of cover 14 exceeds that of the upper margin 20 of container 10 so that the cover can be facilely placed on the container. The difference is not great however, since by the time the cover is inserted so that shoulder 40 is seated on lip portion 22, the sides fit snugly around the lip.

Each lower side portion 38 includes a relatively small spherical protuberance, dimple, or indent 52, 52a extending inwardly from the inner surface. lndents 52 and 52a provide both a latching and camming function for releasably locking the cover to the container. As the cover is inserted over the container, the lower margin 50 of the cover slightly clears the upper margin 20 of the container and is assisted along all four sides by the engagement of indents 52 and 52a which cam the lower side portions 38 of the cover around the upper margin 20 of the container. in addition, the indents 52, 52a are positioned beneath shoulder 40 a distance slightly in excess of the height of lip 22 so that as shoulder 40 seats on the upper margin 20 of sides 18, indents 52, 52a spring back beneath keeper surface 24 latching the cover to the container. To release the cover, one simply flexes one of the lower side portions 38 of cover 14 outwardly until indents 52, 52a are released from engagement with keeper surface 24 whereupon the cover is lifted somewhat pivotal 1y off the container.

The indents 52, 52a are located strategically on the cover to both facilitate and permit deflection of the resilient plastic while camming the cover on or off. The

effectiveness of the latching aspect of the indents is determined by: (l) the vertical positioning of the indents relative to the mating surface (lip 22, FIG. 4); (2) the size of the projection of the indents; and (3) the horizontal position of the indents relative to their vertical positioning and size as well as the corners of the cover. Thus, depending on the physical dimensions of the container, the selection of the location of indents 52 and 52a will determine their effectiveness both in camming and latching.

Referring now to FIGS. 13, the upper side portions 36 of cover 14 are formed with a plurality of longitudinally spaced generally vertically extending ribs 54 which terminate at their lower end at shoulder 40 and at their upper end with top 30. Preferably, the upper terminal end 55 (FIG. 1) of each rib 54 is curved from the vertical to the horizontal for added strength. The upper terminal ends 55 extend across a marginal edge 31 of top 30 which extends around the periphery of the top and is offset or recessed from the general plane thereof. The top 30 of cover 14 includes a central recess 56 forming a generally upstanding wall 58 around its periphery. In effect, then, wall 58 is an area offset or raised from the levels of marginal offset or recess 31 and central recess 56 which extends along and adjacent to the top edge or periphery as shown in FIG. 3. The ribs 54 with upper ends 55 form a continuation or extension of this raised level as they extend across margin 31 and down side portion 36. The net effect of ribs 54 and wall 58 is to greatly enhance the overall strength of cover 14 to resist deflection from both vertical and transverse loads. This strength is particularly realized in the vertical direction since one of the benefits of the unique cover of my invention is the ability to withstand vertical stacking of a plurality of containers during both shipping and display. The overall strength of the cover in this regard has never heretofore been possible from a vacuum-formed very thin thermoplastic material. Such a cover is, of course, extremely more economical to manufacture in mass quantities.

The cover of the invention is thus economically attractive from a production standpoint since the preferred vacuum-formed process is far cheaper than other molding processes such as injection molding or stamping. The cover is extremely easy to put on and take off of the container with the indents forming the latch also acting as a cam to facilitate insertion and removal.

Although but one embodiment has been shown and described in detail, it will be obvious to those having ordinary skill in this art that the details of construction of this particular embodiment may be modified in a great many ways without departing from the unique concepts presented. It is therefore intended that the invention is limited only by the scope of the appended claims rather than by particular details of construction shown, except as specif cally stated in the claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A container and a cover for said container suitable for packaging, protecting and displaying frangible goods, said container comprising: sides defining a general cup shape; a lip projecting outwardly from the top of said sides in a generally horizontal direction and then turning generally vertically and having a height in a vertical orientation and having a top surface; said lip forming at least one corner; said cover being formed of a one-piece transparent resilient plastic material and having a lip engaging surface generally at the periphery thereof for engaging said top surface of said lip, and sides extending generally downwardly from said surface constructed to extend over and engage at least portions of said lip, said cover sides meeting and forming at least one corner having an apex; at least two inwardly protruding dimples formed in said downwardly extending sides at a position below said lip engaging surface a distance slightly greater than said height of said lip whereby said dimples will lock under said lip when said cover is in place; each said dimple being closely adjacent the apex of said corner in one of the sides forming said apex, thereby forming a pair of cooperating dimples, said pair having dimples opposing one another across said apex of said corner, the inwardly extending portions of each of said dimples cooperating to latch under said lip of the container forming said container corner to hold the cover to the container.

2. The improvement according to claim 1 wherein said container and said cover include a plurality of corresponding ones of said corners, one of said dimples being positioned closely adjacent the apex of each corner on each of the sides of said cover thereby forming a pair of cooperating dimples having dimples opposing one another across the apex of each of said corners whereby each corner of said cover can be latched to each respective corner of said container.

3. The improvement according to claim 2 wherein said cover is differential-pressure formed.

4. In a container and cover suitable for packaging, protecting and displaying frangible goods contained in said container, said cover having a top and sides defining a general cup shape, said cover being differentialpressure formed of a one-piece transparent resilient plastic material the improvement comprising: said container including an outwardly projecting and vertically turning lip having height in a vertical direction said lip being an upper surface; said cover top being generally planar and including a marginal portion adjacent the edge of said top and offset from said general plane, said sides having a first portion extending downwardly from said top and a second portion extending downwardly from said first portion, the transition between said first and second portions defining a transverse shoulder extending outwardly from said first portion and inwardly from said second portion the interior surface of which seats on said upper surface of said lip and indexes the cover relative thereto; said top including a central portion offset from said general plane of said top to increase the rigidity and stability thereof; said top and upper side portions including spaced portions integral therewith, extending across said marginal offset portion, and formed out of the planes of said top and side portions away from the interior of said cover to increase the resistance of said top or side to deflection from vertical and transverse loads; and said cover including latch means integral with said second portion of said sides and spaced from said shoulder a distance at least equal to said height of said lip to releasably latch said cover to said container.

5. The improvement according to claim 4 wherein the inner margin of said shoulder is aligned with the inner margin of said lip of said container when said cover is placed over the container and latched thereto.

6. The improvement according to claim 5 wherein the transverse width of said shoulder corresponds to the transverse width of said lip of said container.

7. The improvement according to claim 5 wherein said shoulder is continuous.

8. The improvement according to claim 4 wherein said latch means includes at least one rounded indent protruding inwardly from the second portion of each said cover sides and spaced beneath said shoulder, said indent being cammed over the upper lip portion of a container and captured beneath said lip portion to releasably lock said cover to said container.

9. The improvement according to claim 8 wherein one of said indents is positioned at each corner of each of the sides of said cover.

10. The improvement according to claim 4 wherein said cover is vacuum-formed from a single sheet of thin thermoplastic material.

11. The improvement according to claim 4 wherein said offset central portion of said planar top includes a recess in said top having a downwardly extending wall around the periphery of said recess which wall provides increased resistance to deflection from vertical or transverse loadings on said cover.

12. The improvement according to claim 11 wherein said spaced portions comprise ribs having a horizontal portion at the upper end thereof terminating along the edges of said top spaced from said recess.

13. The container and cover of claim 1 comprising: each of said sides of said cover including an upper and lower portion separated by a shoulder extending generally normal to said sides, said shoulder defining said lip engaging surface seating on said top surface of said lip to index said cover on said container, the width of said shoulder corresponding to the width of said lip, said dimples comprising spherical-shaped protuberances.

14. The combination according to claim 13 wherein the upper portion of said sides includes one or more vertical standing rib portions and the top of said cover includes an offset portion defining a generally upstanding wall portion along the periphery of said offset portion, said ribs and wall portion providing increased resistance to deflection from vertical and transverse loads.

15. The combination according to claim 13 wherein said cover is vacuum-formed from a thin sheet of thermoplastic material.

16. The improvement of claim 4 wherein said central offset portion is recessed to a level approximating that of said marginal offset edge portion of said top thereby forming a raised offset area therebetween along and adjacent to the edge or periphery of said top.

UNITED PATENT OFFICE CERTIFICATE OF COYRRECTIZON Patent No. 3337 .526 Dated September 24 1974 Inventor(s) RogerL. Medendorn It is certified that error appears in the above-ideritified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1, line 132 Aft.e r"'vertical" omit "and handling'and shipping an d'fyet have sufficient vertical".

signed and sealed this 31st day of December 1974.

(SEAL) Attest: I

MCCOY MQIIGIBSON JR. 0. D'iARSHALLfDANIZ Attesting ,Officer Commissioner of Patents USCOMM'DC 60376-P69 FORM P0-1050 (10-69) a u.s. sovzauuzu-r PRINTING OFFICE: I969 o-see-su, 

1. A container and a cover for said container suitable for packaging, protecting and displaying frangible goods, said container comprising: sides defining a general cup shape; a lip projecting outwardly from the top of said sides in a generally horizontal direction and then turning generally vertically and having a height in a vertical orientation and having a top surface; said lip forming at least one corner; said cover being formed of a one-piece transparent resilient plastic material and having a lip engaging surface generally at the periphery thereof for engaging said top surface of said lip, and sides extending generally downwardly from said surface constructed to extend over and engage at least portions of said lip, said cover sides meeting and forming at least one corner having an apex; at least two inwardly protruding dimples formed in said downwardly extending sides at a position below said lip engaging surface a distance slightly greater than said height of said lip whereby said dimples will lock under said lip when said cover is in place; each said dimple being closely adjacent the apex of said corner in one of the sides forming said apex, thereby forming a pair of cooperating dimples, said pair having dimples opposing one another across said apex of said corner, the inwardly extending portions of each of said dimples cooperating to latch under said lip of the container forming said container corNer to hold the cover to the container.
 2. The improvement according to claim 1 wherein said container and said cover include a plurality of corresponding ones of said corners, one of said dimples being positioned closely adjacent the apex of each corner on each of the sides of said cover thereby forming a pair of cooperating dimples having dimples opposing one another across the apex of each of said corners whereby each corner of said cover can be latched to each respective corner of said container.
 3. The improvement according to claim 2 wherein said cover is differential-pressure formed.
 4. In a container and cover suitable for packaging, protecting and displaying frangible goods contained in said container, said cover having a top and sides defining a general cup shape, said cover being differential-pressure formed of a one-piece transparent resilient plastic material the improvement comprising: said container including an outwardly projecting and vertically turning lip having height in a vertical direction said lip being an upper surface; said cover top being generally planar and including a marginal portion adjacent the edge of said top and offset from said general plane, said sides having a first portion extending downwardly from said top and a second portion extending downwardly from said first portion, the transition between said first and second portions defining a transverse shoulder extending outwardly from said first portion and inwardly from said second portion the interior surface of which seats on said upper surface of said lip and indexes the cover relative thereto; said top including a central portion offset from said general plane of said top to increase the rigidity and stability thereof; said top and upper side portions including spaced portions integral therewith, extending across said marginal offset portion, and formed out of the planes of said top and side portions away from the interior of said cover to increase the resistance of said top or side to deflection from vertical and transverse loads; and said cover including latch means integral with said second portion of said sides and spaced from said shoulder a distance at least equal to said height of said lip to releasably latch said cover to said container.
 5. The improvement according to claim 4 wherein the inner margin of said shoulder is aligned with the inner margin of said lip of said container when said cover is placed over the container and latched thereto.
 6. The improvement according to claim 5 wherein the transverse width of said shoulder corresponds to the transverse width of said lip of said container.
 7. The improvement according to claim 5 wherein said shoulder is continuous.
 8. The improvement according to claim 4 wherein said latch means includes at least one rounded indent protruding inwardly from the second portion of each said cover sides and spaced beneath said shoulder, said indent being cammed over the upper lip portion of a container and captured beneath said lip portion to releasably lock said cover to said container.
 9. The improvement according to claim 8 wherein one of said indents is positioned at each corner of each of the sides of said cover.
 10. The improvement according to claim 4 wherein said cover is vacuum-formed from a single sheet of thin thermoplastic material.
 11. The improvement according to claim 4 wherein said offset central portion of said planar top includes a recess in said top having a downwardly extending wall around the periphery of said recess which wall provides increased resistance to deflection from vertical or transverse loadings on said cover.
 12. The improvement according to claim 11 wherein said spaced portions comprise ribs having a horizontal portion at the upper end thereof terminating along the edges of said top spaced from said recess.
 13. The container and cover of claim 1 comprising: each of said sides of said cover including an upper and lower portion separated by a shoulder extending generally normAl to said sides, said shoulder defining said lip engaging surface seating on said top surface of said lip to index said cover on said container, the width of said shoulder corresponding to the width of said lip, said dimples comprising spherical-shaped protuberances.
 14. The combination according to claim 13 wherein the upper portion of said sides includes one or more vertical standing rib portions and the top of said cover includes an offset portion defining a generally upstanding wall portion along the periphery of said offset portion, said ribs and wall portion providing increased resistance to deflection from vertical and transverse loads.
 15. The combination according to claim 13 wherein said cover is vacuum-formed from a thin sheet of thermoplastic material.
 16. The improvement of claim 4 wherein said central offset portion is recessed to a level approximating that of said marginal offset edge portion of said top thereby forming a raised offset area therebetween along and adjacent to the edge or periphery of said top. 